public class P4_Ptry2{
	public static void main(String args[])
	{
		Line l1 = new Line(3, 3, 4, 4);
		System.out.println(l1.length());
	}
}

class Point{
	protected int x, y;
	Point(int a, int b)
	{
		setPoint(a, b); //System.out.println(this.x + "  " + this.y); 
	}
	public void setPoint(int a, int b) { x = a; y = b; }
	public int getx() { return x; }
	public int gety() { return y; }
}

class Line extends Point{
	
	Point endp;
	Line(int x1, int y1,int x2,int y2){
		super(x1,y1);
		
		setLine(x2, y2);
		
	}

	public void setLine(int endx , int endy){
		endp = new Point(endx, endy);
	}

	
	public double length(){
		return Math.sqrt((endp.getx() - super.getx()) * (endp.getx() - super.getx()) + (endp.gety() - super.gety()) * (endp.gety() - super.gety()));
	}
}